Your apache server is heavy loaded.
You have too much to do. For example, some (not exhaustive) tasks to do:
-1) Know your sites;
-2) know your hosted scripts;
-3) watch all apache logs carefully;
-4) know how your firewall works;
-5) Install Mod_Security;
-6) Parse *every* day some parsing logs software, like "LogWatch", or "Logcheck";
-7) React to every attack manually, and improve *everyday* the configuration of the firewall, to react automatically as much as possible
-8) Know and improve the configuration of you webservers/Apache server, to balance loads;
-9) Optimize your database access;
-10) Optimize the priority of your processes to meet your demand, optimizing your load.
In other words, your must administer your server and your Apache server with hard work, everyday.
And this could demand some experience, that you will acquire just working every day in every aspect of your server.
It may be that your server is unable to meet your demand too, but we can only conclude this after doing the above analysis.
Regards,
Netino